//第四题
import java.util.Scanner;
public class M80604 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入需要的钢管长度(米): ");
        double requiredLength = scanner.nextDouble();
        int numberOfPipes = (int) Math.ceil(requiredLength / 3);
        System.out.println("您需要购买 " + numberOfPipes + " 根3米长的钢管。");
        scanner.close();
    }
}